I have posted about this in the past but it was never figured out, and I have since noticed a couple of other symptoms and replaced some parts that may help in figuring this out.

I have a 2000 Civic Hatch with a 2000 GSR swap and a JDM ITR tranny. There are no heat shields, everything is tight, and there are otherwise no easy answers to this problem.

THE PROBLEM: When driving in 4th or 5th gear with foot off the gas, there is a metallic buzzing/rattling sound that is coming from the engine bay, audible through the shifter opening. The noise goes away completely when I either press in the clutch and/or take it out of gear, or when I step on the gas even very slightly.

The noise was always there since the day I bought the car. During the course of trying to figure out the source of this noise I have replaced all of the following parts which I consider could be relevant to the problem:

- Transmission (three times)
- Clutch, PP, flywheel, throwout bearing
- Clutch slave cylinder
- Shift linkage/****
- Header
- Exhaust
- Cat converter
- Intermediate shaft/axles
- Steering rack

Can anyone please give me some suggestions on what part you think could be causing this noise given the symptoms (i.e. taking it out of gear or stepping on the gas makes the noise go away)?

ANY ideas/pointers would be greatly appreciated - I am at the end of my rope on this one and really don't know where else to look or what to replace.

TIA

 

Maybe your exhaust is rattling itself apart? Could try there. Or yoour cat is falling apart maybe? Highly unlikely, but possible.

 

I have replaced both recently, and the noise was clearly audible then. The new exhaust is a Mugen Twinloop (catback), and the cat is a stock GSR cat. I just tried out another cat, and the noise was definitely still there, so it's none of these components.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dynamo &raquo;</TD></TR><TR><TD CLASS="quote">I have replaced both recently, and the noise was clearly audible then. The new exhaust is a Mugen Twinloop (catback), and the cat is a stock GSR cat. I just tried out another cat, and the noise was definitely still there, so it's none of these components. </TD></TR></TABLE>

i have this same problem with my b16 in me 93 hatch. it started ater i did the swap. i've double checked everything just like you and the only conclusion i came up with is maybe it's the cat itself.

my rattle ranges between 3500-5500 rpms. whether i'm in idle or not.
if you figure this out, please let us know, it drives me crazy too.

 

Yours sounds like an exhaust/cat problem, but unfortunately that is not the case with mine. The first place I would look if I were you would be in the b-pipe/resonator, from what I understand those are weak spots in Honda exhausts (assuming yours is stock). If it isn't, the cat is the next place to look.

Generally, from what I have read/experienced on my own is that rattles that happen in a certain RPM range tend to be exhaust related. Mine, however, seems to be more of a drivetrain issue - if only I could figure out what the hell it could be!

 

 

Heat shield?

 

No heatshields anywhere.

 

Are you able to get the noise if you hold a certain RPM in neutral?

maybe get your car up, and someone inside to run the gas so you could pinpoint the noise underneath the car.

I had a similar noise, ended up being the cat heatshield was vibrating, but i dunno since u dont have heat shields anywhere

good luck

 

Nope, the noise happens ONLY while in gear and is most audible at above 2,500 RPM. The noise decreases as the car decelerates and the RPM's go down, and disappears completely when it's out of gear.

I have replaced pretty much everything that I thought could be related to the noise, and heat shields were the first things to go - there isn't a single one under there.

So, after trying pretty much everything I am at the end of the road and am getting pretty desperate even for suggestions - no one seems to have a clue of what it could be.

 

you have a short shifter? mine did the same thing. rattled in gear and went away at lower rpms or with clutch in. I didn't set the o-rings properly and not enough grease. just a guess.

 

Nope, I have a stock ITR shifter with stock ITR linkage. Prior to that I had an Si shifter and Si linkage, and the noise was still there.

 

the shield around the resonator?

 

That one is removed as well, plus, I am 99.9% positive that the noise is coming from the front of the car/engine bay area. I took the center console pieces out exposing the hole that the shifter goes through, and I am almost certain the sound is coming from the front of the car.

 

Did you replace the tranny or just take it off 3 times? It could be you lsd going bad(bearings)

 

The tranny has been replaced three times. The first tranny did not have an LSD, the second one did (but it was leaky), and the third one is a fairly new ITR one with an LSD. The noise has been present with all three trannies, so I think the tranny is safe to rule out (along with everything else on the list up top).

I think the key to solving this problem is the fact that the noise goes away as soon as I apply even the slightest pressure to the gas pedal. Can anyone think of anything else that is affected by the throttle that would be making noise when no throttle is being applied?

 

could be your just hearing the niose the gears make, check your oil level in the tranny. you should be using 90 weight gear oil.

 

Do you have a cat? (converter, I wasn't rying to be funny)

Nevermind, reading &gt; me.

I was thinking your cat **** itself and was loose inside it's housing.

 

I am using the GM synchromesh tranny fluid, same one my roommate is using in his S2000. I also used the stock honda MTF in the previous trannies, and the noise was still there. UGH!!!!!

 

maybe you can look under the car and find that its hitting something?

 

Pcv valve makes noises like that. Bypass it see if its just that.

 

I have spent countless hours under the car with a mallott, hiting everything in sight and never found anything. The only time I can reproduce the noise is when the car is in motion, in gear, and under the conditions described in my original post (i.e. foot off the gas).

 

I am looking at the diagram of where the valve is, and not sure how I could bypass it. Any suggestions on how to do it? Also, why do you think it could be that particular part - do you think it matches the conditions I described? Thanks for the tip either way - I haven't tried this one yet!

 

It make sounds like that under vacume. pull the line from the intake mani and cap it, That should bypass it. But dont leave it like that for long.

 

Great, thanks for the tip I'll try it out tonight or tomorrow. If bypassing it gets rid of the noise, do I simply replace the valve or is that normally what it sounds like?

Still looking for other suggestions - I've tried pretty much everything at this point so I'm looking for a list of things to try out to get rid of this damn noise!!!